Patent GB-990684-A (GB)
Title: Driving means in a track system
IPC: F16H19/02
Filed: 1961-12-27
Abstract: 990,684. Friction gearing. TRANSPORTPATENT A. B. Dec. 27, 1961 [Dec. 27, 1960], No. 46349/61. Heading F2Q. [Also in Division B7] In a track system carriages are driven along rails by means comprising a rotatable driving shaft 3 extending parallel to the track and a freely rotatable driving wheel 7 on each carriage, which is resiliently urged by a spring 13 against the driving shaft, in such a position that the axis of rotation of the driving wheel 7 forms an angle with the axis of rotation of the driving shaft, the wheel 7 being mounted for swinging movement on a pivot 10, which extends perpendicularly and eccentrically to the axis of rotation of the driving wheel. The shaft 3 is mounted in bearings, each comprising three symmetrically spaced rollers, preferably of plastics material, situated so as to leave the top of the shaft 3, free from obstruction. The track system may be provided with a main track and with branch tracks at right angles thereto, each track having its own driving shaft 3. In the embodiment shown in Fig. 2, a bearing support 8 is secured to the body of a carriage and this carries a bushing 9 for the pivot 10. Two spaced fork arms 11 fixed to the pivot 10 support the wheel 7 and a tension spring 14 acts between a fixed pin 15 and a lug 16 on one of the fork arms 11, so as to keep the rotation axis of the wheel 7 at an angle to that of the shaft 3. If the carriage is stopped by an obstruction, the tension of the spring 14 is overcome and the rotation axis of the wheel 7 becomes parallel to that of the shaft 3 so that the wheel 7 merely rolls on the shaft 3. Stops 18, 19 acting on an arm 17 fixed to the pivot 10 prevent excessive swinging movement of the wheel 7. In the embodiment shown in Fig. 4, the wheel 7 is held at an angle to the shaft 3 by a spring 21 acting on an arm 20, fixed to the pivot 10. The wheel 7 may then move to positions in which its rotation axis is parallel to either of two shafts 3 crossing each other at right angles. The swinging movement of the wheel 7 is limited by a stop pin 18, which co-operates with an arcuate slot 18a in an arm 19h projecting from the arm 20. In a further embodiment (Fig. 5, not shown), the wheel 7 is held by a compression spring acting on the arm 20, in one of two positions in which its rotation axis is at an angle to that of the shaft 3, so that the carriage may be driven in either direction along the track. When the rotation axis of the wheel 7 and the shaft 3 are parallel the spring is compressed and the wheel may be held in this position by retractable stops. At positions in which it is desired to stop the carriages along the track tapered end portions 29, Fig. 4, are provided on the driving shafts 3 and these are preferably separate from the driving shafts and driven therefrom through a universal joint, each end portion 29 being arranged so that its upper surface is level with that of the associated driving shaft 3. A carriage will be decelerated or accelerated depending on which direction it is travelling on an end portion 29. Each driving wheel 7 is preferably surfaced with rubber or a plastics material. Specification 963,154 is referred to.